1. Field of the Invention
The present invention generally relates to service quality management in network communications, more particularly to a technology for providing service quality guarantees to the services of network service providers in accordance with their business strategies, and specifically to a method, a system, a program, and a readable storage medium for providing service quality guarantees to a network service.
2. Description of the Related Art
More and more new services currently appear in the packet network. Many of these new services, such as IP telephones, network teleconferences and IP televisions etc., are very sensitive to service qualities. How to effectively guarantee the service qualities of these services is a central problem encountered upon large-scale deployment of these services. Conventional technology and methods for service quality guarantee are mainly divided into the following three types:
1) Excessive setup: this method guarantees the qualities of all network services by providing network resources that are far more than necessary.
2) Multi-protocol label switch (MPLS) and quality of service (QoS): this method guarantees service quality of services having high priorities by managing/adjusting network resources based on a “hierarchical service” frame and multi-protocol label packet technology.3) Service flow limitation: this method presets an upper limit to the number of active service flows permissible on certain paths in a network, and newly arriving service flows will be denied once the number of the active service flows on these paths reaches this upper limit.
The aforementioned first type of method is most widely applied in the current networks. This is because it is simple in the setup method and no additional functional support by network devices is needed. However, its defects are obvious. As the term itself suggests, “excessive setup” means waste of network resources. What is more important is the fact that, once great changes occur in the network flow, the guarantee provided by “excessive setup” will become invalid.
The aforementioned second type of method is a hot spot of the current research. However, large scale application of this method requires that all network nodes support the functions of MPLS and QoS, and calls for excellent interoperability in these functions. This is impossible to achieve for most current networks.
The aforementioned third type of method demands a great deal of meticulous manual setup, and requires that all service requests be processed by the controlling devices thereof. This makes it impossible for this type of method to be applied in a large scale in the networks.
At the same time, the aforementioned three types of methods share a common defect. It is that network service providers cannot manage or control the guarantees of the service qualities in accordance with their individual operational strategies. To the network service providers, operational strategies are precisely the key for them to subdivide the market and enhance competitiveness.
In the conventional art, technologies relating to the service quality management of network communications generally include measurement technology, monitor technology, and control technology, of which the existing measurement technology merely measures the average network performance within a given time period or measures the network performance before a service flow starts. Such measurement technology cannot measure the quality of the network service in real time.
In the course of monitoring service quality, how to determine the bottom line of service quality and hence determine the degradation and recovery of service quality is one of the most important aspects. In the existing monitor technology, the bottom line of service quality is usually determined by either one of the following two modes: historical service quality, and 2) invariant parameter value. In the first mode, variations (changes) of service quality are restricted within historical variations (changes), and degradation is considered to have occurred once the variations (changes) exceed the historical variations (changes). However, service quality may still actually be good even where the variations exceed the historical variations. In the actual networks, since service quality changes frequently, the “excessive control” engendered by this mode not only greatly increases additional control load but at the same time affects the throughput of the network. Meanwhile, the second mode determines degradation to have occurred only when the service quality is worse than a predetermined parameter value. This mode neglects the fact that service qualities of the same network might be different between service node pairs or at different time periods of the same pair of nodes. For example, although it may be normal to increase the delay by 10 ms for a pair of nodes whose service delay is usually 50 ms to 60 ms, the same variation may be a sign of severe service quality degradation for a pair of nodes whose service delay is usually 5 ms to 10 ms. Therefore, since such a mode with a predetermined parameter value neglects the differences in regionality and timeliness of network service quality, it may be referred to as a “post-reaction” system, in other words, it alerts degradation only after the service quality has severely degraded, thus guarantee of service quality cannot be achieved.
In the conventional control technology, since a quality management (QM) server has to actively measure service quality and analyze the variations of the service quality in order to determine as how to adjust the control policy, the load of the QM server becomes aggravated and the adjustment efficiency of the control policy decreases.
The conventional system, apparatus, and method for controlling the quality of network communications are disclosed, for example, in European Patent Application 00114780.0.